In the load handling art, particularly in regard to vehicles which transport loads a short distance for positioning at various heights, there are numerous schemes to pick up and deposit the load. Most common among these schemes is the forklift vehicle. The forklift vehicle, as is well known, consists of a vehicle having a mast at one end upon which a carriage is mounted for vertical movement. A load handling device is fixed to the carriage so that the vehicle may be positioned adjacent a load to pick up and transport the load from one position to another. Most widely used with this type of vehicle for load handling are a pair of forks which are affixed to the carriage and extend outwardly in front of the vehicle. The forks serve to pick up a container or some other load for movement.
It is quite often necessary to adjust the spread between the two forks on the carriage in order to accommodate the vehicle to various types of loads. Further, should the vehicle need to be transported from one site to another, it is appropriate to either remove the forks or to rotate the forks rearwardly so that the overall length of the vehicle is shortened.
In order to accomplish variable separation of the forks, it has been common to mount the forks on the lift vehicle carriage in a manner that allows for a finite number of positions of the forks. This has been accomplished, for example, by a series of notches along the top of a bar or plate that forms a portion of the carriage. The forks are laterally slidable along the bar and have fitted at the upper end of the fork a pin or the like which engages a notch on the bar at the selected position of the fork. Generally, one type of arrangement has a hooked upper end on the fork to fit over the carriage plate or bar, thereby preventing rotation of the forks.
A second common method for mounting forks on the carriage of a lift truck uses a bar having a finite number of openings in the bar so that a U-shaped locking member may be dropped through the holes to retain the fork in one of a finite number of positions.
Forks have also been mounted on cylindrical bars so that the fork may be rotated about the bar into a retracted position alongside the vehicle. Generally, in this type of installation it is usually necessary to remove the locking pins to permit rotation of the fork.
The problem associated with all of the prior art installations are that the forks are limited to a finite number of positions along the mounting member because of the necessity to position a pin in either a notch or a hole to retain the fork. Further, the forks may be precluded from rotation to a stowed position by the nature of the mounting member, or may require removal of the locking pin to permit rotation.